The Change of Lacrimal Gland Volume in Korean Patients with Thyroid-associated Ophthalmopathy

Abstract

Purpose: To describe the change of lacrimal gland volumes in Korean patients with thyroid-associated ophthalmopathy (TAO) via computed tomography (CT).

Methods: A retrospective review of CT images from 217 TAO patients and 135 control subjects was performed. The TAO patients were diagnosed between May 2005 and May 2014 and had a CT performed on initial presentation (330 orbital CT scans). These images were compared with 270 orbital CT scans from the control group, obtained between May 2013 and May 2014. An open source DICOM viewer was used to calculate the volume of the lacrimal gland.

Results: The mean volume of the lacrimal gland in TAO patients was 0.816 cm³ in the right orbit (standard deviation [SD], 0.048) and 0.811 cm³ in the left orbit (SD, 0.051), with no significant difference between right and left (p = 0.192). However, significant differences were observed between TAO patients and healthy individuals (p < 0.001). There was no significant difference between mean lacrimal gland volumes of males (0.812 cm³; SD, 0.037) and females (0.816 cm³; SD, 0.029) (p = 0.513). There was a negative correlation between gland volume and age in TAO patients (Pearson r = -0.479, p = 0.00). The subjective tearing (right: r = 0.244, p = 0.018; left: r = 0.226, p = 0.024), corneal superficial punctate keratopathy (right: r = 0.192, p = 0.040; left: r = 0.206, p = 0.036), and exophthalmometry (right: r = 0.182, p = 0.032; left: r = 0.180, p = 0.046) correlated with lacrimal gland volume.

Conclusions: This study is the first to use CT images to calculate the lacrimal gland volume of Korean TAO patients. In TAO patients, the lacrimal gland volume was notably increased compared to control subjects. The lacrimal gland volume decreased with age, but there was no difference between gender and no difference between left and right. The lacrimal gland volume correlated with subjective tearing, corneal superficial punctate keratopathy and exophthalmometry.

Keywords: Age group; Computed tomography; Computer communication network; Lacrimal gland; Thyroid-associated ophthalmopathy.

Fig. 1. Axial computed tomography scan viewed on the DICOM viewer (OsiriX, Geneva, Switzerland) with the entire lacrimal gland outlined.

Fig. 2. Scatter plot and correlation between age and average lacrimal gland volume (cm³) in thyroid-associated ophthalmopathy (TAO) patients. B means an inverse relationship between gland volume and age in TAO patients; Pearson r = -0.479 (p = 0.00). A means an inverse relationship between gland volume and age in male TAO patients; Pearson r = -0.328 (p = 0.00). C means an inverse relationship between gland volume and age in female TAO patients; Pearson r = -0.588 (p = 0.00).

Fig. 3. Scatter plot and correlation between age and average lacrimal gland volume (cm³) in control subjects. B means an inverse relationship between gland volume and age in control subjects; Pearson r = -0.802 (p = 0.00). A means an inverse relationship between gland volume and age in male control subjects; Pearson r = -0.772 (p = 0.00). C means an inverse relationship between gland volume and age in female control subjects; Pearson r = -0.830 (p = 0.00).